1. Field of the Invention
The present invention relates to a parallel fieldbus network-based motor control system, and more particularly, to a system which may include one or more slave modules that control one or more motors and correspond to each of the one or more motors, and a master module that generates command data for controlling each of the one or more motors and transmits the generated command data to each of the one or more slave modules, wherein each of the one or more slave modules includes a basic processor and an auxiliary processor, the auxiliary processor acquires the command data from the master module via a basic network, and supports the acquired command data to be stored in a shared memory and transmitted to the basic processor or transmits the acquired command data to the basic processor via a local network, the basic processor controls the motor corresponding to the corresponding slave module in accordance with the command data acquired from the master module via the basic network, read from the shared memory, or transmitted via the local network or supports to control the motor, and supports result data executed in accordance with the command data to be stored in the shared memory and transmitted to the auxiliary processor or transmits the result data to the auxiliary processor via the local network, and when abnormality occurs in the basic network, the maser module provides the command data to the basic processor or the auxiliary processor via an auxiliary network or a wireless network, and the auxiliary processor provides the result data to the master module via the auxiliary network or the wireless network, or acquires command data for continuing to control the motor corresponding to the corresponding slave mode from the master module and supports the acquired command data to be stored in the shared memory and transmitted to the basic processor or transmits the acquired command data to the basic processor via the local network.
2. Discussion of Related Art
A centralized control system has a structure in which a single host device controls and manages all sub units and has been mainly applied to small-scale systems effectively. In such a control structure, control performance may be deteriorated due to an increase in a load on the host device along with an increase in a size of a target system and the whole system may be stopped due to the influence of a failure having occurred in a single constituent component so that reliability of the system may be significantly reduced. In recent years, a distributed control system has been actively studied as an alternative.
The distributed control system is a system that minimizes the influence of a partial failure by distributing control operations for each function, and there is a network-based distributed control system as a representative example of the distributed control system. The network-based distributed control system in which each sub system and a control device are connected via a network may minimize the wiring required to configure a system and have a flexible structure which the network has, thereby increasing scalability of the system. In addition, the network-based distributed control system may unify the management system of a system via a network, thereby increasing operability of the system.
As an example, control devices may be connected to a network-based distributed motor control system via a network so that the network-based distributed motor control system may control a plurality of driving units constituting automation equipment, robots, IoT (Internet of Things), etc. In particular, the network-based distributed motor control system has been widely used in a CAN (controller area network), an RS-485 network, and the like in the way that it can be installed for each joint of a robot, easily managed, and miniaturized. In recent years, EtherCAT network technology that supports a rate of 100 Mbps in order to ensure a high control rate of 1 KHz or higher has been applied even to a motor control system that drives several tens of motors or more at the same time.
However, in the motor control system including an EtherCAT network, a plurality of nodes are connected to a single network in the form of a daisy chain, so that the entire control system cannot be operated normally when a malfunction or a failure occurs in a single network node among the plurality of nodes.
As a result, the present inventor has invented a motor control system which may continue to control the corresponding motor through a basic network and a separate auxiliary network or wireless network when a malfunction in a network node occurs while controlling each motor based on the basic network, so that the entire control system may maintain unique function and performance.
Meanwhile, a conventional motor control system generally controls a motor while focusing on speed and position control of the motor, but due to emergence of application fields in which even current control is further performed, stable control mode switching among control modes of the motor control system such as a position control mode, a speed control mode, and a current control mode has recently become an important issue.
Therefore, the present inventor has invented control technology capable of stably operating a motor without sudden discontinuous movement or impact when switching the control mode.